Threading tool



April 9, 1940. w. M. EMERY THREADING \TOOL Filed July 8, 1938 2Sheets-Sheet 1 INVENTOR. CJz'Z/mm 777197267 WM G9 ATTORN 5 w, M. EMERYTHREADING TOOL Filed July 8, 1938 2 Sheets -Shee't 2 INVENTOR. 7% 6m 67M Q ATTOR 5.

BY llz'lliam Patented Apr. 9, 1940 UNITED," S ATES THREADING TOOLWilliam M. Emery, Cleveland-Heights Ohio, ass signer to The OsterManufacturing Company, v Cleveland, Ohio, a corporation of OhioApplication'July 8, 1938, Serial No. 218,109

' S CIaim's. (o1. 10 s9 This invention relates to threading tools forpipes, bolts and rods, and'is particularly directed towards a'hand'operated die stock tool with a geared drive to give an advantageouspower ratio;

together with more efiicient feed arrangements, quick release, quickreset, and adjustment for over or under size threads'whichis not thrownout;

gagement of the tool with the work.

. In. general, my inventiongives to the user a more smoothly cuttingtool, less fatiguing tonthe 20 operator, easier started, quicker inaction, and

ated die stock, and primarily intended to be so used, it will be obviousthat the invention is not I limited to manual operation, but isapplicable either in all.-.particulars or in Various details to powerstocks.

One of the advantages in connection with my gear drive is that thedirection of rotation of the 36 handles is the same as the direction ofthe rotation of the dies upon the work, just'as in an ordinary stock, sothat theoperator 'is not confused by any, opposite movement of parts. 7

To'the accomplishment of the. foregoing and 35' related ends, saidinvention, then, consists of the means hereinafter fully described andpar ticularly pointed out in the claims.

The annexed drawings'and the following description set forth in detailcertain mechanism 41 embodying my'invention, such disclosed meansconstituting, however, only some of various mechanical forms in which.the principle of my invention may be used.

In said annexed drawings 4 5 Fig.'1 is an axial central section througha preferred form of my threadingtool on the plane .I-I of'Fig. 2, withcertain features in elevation; Fig. 2 is a transverse section on theplane II-II of Fig. 1, with certain features in eleva- 50 tion; i

Fig. 3 aplane development of a lead cam slot; v Fig. 4 is a planedevelopment of a modified lead cam slot; l 65- Fig. 5 is anaxial'sectionthroughn modified still another purpose is to assist theinitial en-.

more adaptable than has'previo-usly been known Although shown anddescribed as a hand-oper form of my invention, on the plane VV of Fig;6, with certain features in elevation;

Fig. 6 is .a face view of Fig. 5, looking in the direction of the-"arrowVI; l C I Fig. 7 isa detail of a modified drive means, 6 applicable tothe tool eitherof Fig. 1 or of Fig. 1 5, and on the same plane as theupper forward portion of either Fig. 1 or Fig. 5'; and

Fig. 8 is a detail illustrating an arrangement both to prevent dies fromfalling out of the die head, and to tend to expand them.

. Referring now to- Figs. 1 and 2, my improved die stock comprises abarrel 1 with a sleeve 2 on the rear and a diehead 3 on the front.Relative I movement is'allowed both axially and circumferentiallybetween-"thesleeve and the barrel, and circtunferentially between thedie head and the barrel. The sleeve carries the usual gripping andcentering fingers 4 adapted to engage the work through cam slots 5 inthe barreland operated 26 by a conventional scroll plate '6 andhandle 1. i The movement of the cam slots 5 along the inwardlyprojecting ends of the fingers 4 gives a starting and leading motiondirectly to the bar rel, and with it-tdthe die'head, as described fig;

hereafter. An adjusting ring 9 is threaded "to' the forward end of thesleeve T2,'and can'be set in adjustment by the lock screw I0. orothersuitable'means- This ring 9 adjusts the dies 8 ma manner explainedlater. The diehead 3 carries 3 the usual dies or chasers B. s

The-die head assembly is composed of various elements and attachments ofa planetary gear system. The foundation ring or reactive gear .is atoothed ring l5 'showninFig. 1 as keyed by 3;, screws "if to the barrelI although of course it could be=inte gral.-- The planetary pinions ll,of which there are two in the present form, are carried on shafts I8 ina cage whereof thefrontmember'is the die head 3 and. the rear member f aring is 'rotatablebn the barrel l and against the rear face of l5, frontand rear-members being fastened together by bolts 20. A driving ringticular-instance. The ring has the usual hanv dle sockets 21.

The dies 8 are'bottomed upon faces 32 out-* wardly and rearwardlyinclined-along axially directed receding studs 34, the front ends ofwhich project through suitable openings at the bases of the die sockets30, and the rear ends of which are notched to the adjusting ring 9. Theinclination of the faces 32 obviously determines the taper of the threadcut, and thus faces 32 with zero inclination (parallel to the axis) willcut straight threads.

The faces 32 terminate rearwardly in. sharply sloping shoulders 36followed by notches 38. The length of the faces v32 determines thelongest cut for which the tool is designed. There is a receding stud foreach die, and at least some of these receding studs may project somedistance in advance of the die head 3 to carry nuts 35 threaded on suchprojections, and short springs 35 between such nuts and the face of thedie head. In the embodiment illustrated in Figs. 1 and 2, there are fourreceding studs, of which two opposite ones have springs while the othertwo, 34', do not project so far forward and do not carry springs. thedies on the work, as explained later.

A suitable arrangement for preventing the dies 8 from falling inward isshown inFig. 8. A spring-pressed detent 40, attached to the face plate 3(or I03, Fig. 6) engages a nick M in the edge of the die strongly enoughto hold the die against gravity, and the nick II is shaped or positionedto tend to press the dies radially outward against receding faces 32.

It is apparent from Fig. 1 that the studs 34 will be set forward or backwith respect to the dies and die head by the position of the adjustingring 9, to which they are engaged by a groove for axial movement. Suchsetting, which is made before work begins, obviously varies the initialradial position of the dies 8, thus causing a deeper thread to bestarted and carried through if the studs are back, or shallower if theyare forward, but without altering either the starting position along theaxis of the work, or the taper of the thread. Since the faces 32 aresomewhat longer than the distance to be threaded, and the axialadjustment which the ring 9 can produce is relatively slight, suchadjustment will not cause the dies to drop into the notches 38 too soon.

The cam slots feed the die head upon the work without relying upon thechaser teeth to do their own feeding. These slots 5 fit over the innerends of the locking fingers 4. The fingers 4 do not move relatively tothe pipe, andfor this reason the fingers 4 and sleeve 2 act as afixedbase for all the movements .of the die stock and its parts, but thebarrel I is subject to the reactive force on the gear I5, which tends toturn it in the opposite sense to the die head. Such tendency is directedby the cam slots 5 (or I05, Fig. 5 to assist in the} starting of thedies upon the work, but the action of the cam slots is not a positivedetermination of -movement, but only a tendency supplementing butsubordinate to the force of advance of the die head as the dies cuttheir way onto the work. With my invention it is accordingly possible tocut-threads of different characteristics with the same die stock, ofcourse using the proper dies, either Whitworth, U. S., Standard, orothers.

The exact cam formation is obviously a matter to be related to thecharacter of the thread being cut, the character of the dies selected toout the thread, and other factors, and the cams are so a designed togive more or less starting force and leading effect. One form of cam isshown developed in Fig. 3, wherein it will be seen that the rearmost orstarting portion of the cam is a curve whose initial slope B is in thisparticular illustra- The springs 35' assist starting tion 60 to theaxial line of the tool, flattening at C to a slope of and furtherflattening out to zero at D, at the front'end. It will be understoodthat these values are illustrative and not limiting. The purpose is tobring the die teeth quickly into engagement with the pipe, and feed atthe proper rate for thread cutting as determined by the die teeth, butwith the principal feeding stress on the cam instead of on the teeth.

The cam of Fig. 3 is recommendedfor cutting a taper thread. With such athread the amount of metal removed by the die throat is greatest at thebeginning of the cut, and progressively diminishes; therefore the amountof pull on is greatest at the beginning and diminishes as the threadingprogresses, and the curve of the cam is thus accordingly designed withthe slope greatest at the beginning.

Where a straight thread is to be out, the amount of metal to be removedby the dies is constant throughout-the length and thus a straight camsuch as 5', Fig. 4, is satisfactory. In Fig. 4, another fiatdevelopment, the portion of the barrel is indicated as I and except forthe shape of the cam it is the same as the barrel I of Fig. 1, or thebarrel IIlI of Fig. 5. A finger 4 fills the end of the cam slot, and thespecific cam illustrated makes an angle of 15? with the axial line A-Aof the barrel, as illustrated by the center line E.

A further pull on effect may be obtained by means of the springs 35,Fig. 1, already mentioned. These springs tend to move the die head 3towards the fingers 4, sliding the barrel I through the sleeve 2. Thuswhen the fingers 4 are clamped on the pipe or rod, and the springs 35'compressed, with the throats of the dies 8. on the end of the work, thesprings have a pull on effeet, which lasts until advance of the die headreleases the compression.

A modified form of my improved threading tool is shown in Figs. 5 and 6.Elements on these figures which correspond to Fig. 1 are indicated, sofar as appropriate, by reference characters IBI) higher than on Fig. 1.In Fig. 4 a work piece'W, in the present instance a' pipe, upon whichthreading is about to commence, is shown in the tool. The rear end ofthe tool is clamped as in Fig. l by fingers I04 passing through slotsI05 in the barrel II. The planetary gearing arrangements are likewisethe same, consisting of an outer ring I25 from which power applied byhandles in sockets I2! is transmitted by an internally toothed gear I26to planetary pinions I I1 which also mesh with the inner gear I I5,shown integral with the barrel IOI in this form.

The dies I08 in the die head I03 are bottomed on the receding faces I32of studs I34, and the studs are notched as at I38 to allow the chascrsto move outward at the termination of their out. The adjustment of theposts I34 for full, medium or shallow cut is by their connection with aspider 50 movable toward or' from a stop bar 52 by a wing headed screw53. The stop bar contacts'the front end of the work W, and a pin 55prevents relative rotation between the bar 52 and the spider 58, so thatthe screw 53 will not betightened or loosened by rotation of the diehead I03; The dies I08 may be held against falling inward by the samemeans as shown in Fig. 8. It is evident from the drawings that varyingthe space between the bar 52 and spider 50 alters the initial radialposition of the dies I08 without changing their axial relation to thetool, so;that..full, medium or shallow threads may be out, just as byadjusting the ring 9 of Fig. 1. r

- In either forin of the" invntiom compound planetary gears IIA,v IIB,Fig. '1, maybe used in- 3 stead of the simple planetarygears, thedriving and reactive gears 26A and I being appropriatelyaltered tol fittheisituation, all as shown in Fig.7, where the reference'characterscorrespond to those of Fig. 1, with suffix A, and the spur gearhigher-order, in excess of 2:1. 1

hasa. large circumference HA and a small circumference IIB.:: I v v Theoperation of the form of invention shown in Fig. '1 will now bedescribed, and that of the form shown in Fig.5 will bed'escribed inthose particulars wherein it differs.

. The pipe, rod or boltis inserted in the barrel, and clamped in theusualmanner with the throat or enteringedges of the dies in. engagementwith the end of the pipe- In the subsequent operations, the studs 4 andsleeve 2 actas a base toward l which the die head of the tool is drawn,chiefly by action of the cam slots- 5, 'andspring (if used) since oneobject of the invention is to relieve the die teeth from feeding work;The

handles 21 are now rotated in the cutting direction, and this motion istransmitted by the planetary reduction gear to the die head 3, thusmoving the dies inthesame direction as the handles, but at a reductionpreferably on theorder of 5:3, say 1.751. With the compound pinions ofFig. '7 thisinay be of a considerably As soon'as frictional contact ismade between the dies and the workxthe' reaction turns the barrel 1oppositely to the die head, causing the cam slot to travel on the 'studsl and so-first start the dies andthen feed them. Iffthe cam slot is thatof Fig. 3, -ior ftaper threading (the usual situation) the bari'el movesat first witha substantial circumferential component, and a slight axialcomponent, as indicated'by slope B, but the proportions ofcircumferential and ax-.

ial components gradually reverse, "for reasons heretofore explained.

' The dies are of cour's'e 'of proper size for what ever work is to beout, according tostanda rd- 4:;

matically open when they travel back to the notches 38, and in soopening the slopes 36 cause the roots of the threads to work out .with asmooth finish instead-ot-an abrupt bur. The notches 38 also serve assafety devices to disengage the dies fromthe work if a power-driven diestock is left running. After the dies are disengaged the die head "turnsidly and thus no damage will result no matter how long the drivecontinues. V i

If only a short thread has been out, the tool is removed from the workwithout unwinding, asfollows; The operator releases the fingers 4 by thehandle I and pulls the rear end of the tool (sleeve 2 and associatedparts 5, I and so on) toward the die head 3. This slides sleeve 2 overthe barrel l so that the notches 38 come under the dies 8, and the dies8 are thus allowed to move radially outward, biased thereto by de--tents Ml acting on the appropriate slopes of notches 41, and furtherassisted, if necessary, by the operator rocking the tool on the pipe.With end in opposite directions.

' on? "the cut threads.)

and the 'feed by the'cam slots-Hi5 will be shaped appropriately to thework,.as already discussed [In the form shown 'in' I 5, the threadingtool is fastened on'the Work'I-W' as'in Fig. 71;] the gear drive is thesame (or 'that of: Fig. 7),,

in describing Figs. 3 and 4. 'Theadjustment for;

' full or shallow threads: is by the spider 513 and stop bar 52, allheretofore described. When the tool. is clamped on the work by the,fingers it' l the adjusting elements can be pushed-back-b-y hand untilthe bar ,52 stops against theQfro'nt as in Fig.1, and the effect is asdescribe'd'for fall into the notches |38"an d"the tool canthen- .end. of.the work, and this places-the-dies IE8 inprope'rjradial position.To-cut threads with, thetool of Fig. '5', the handles are turned justthat figure At the'endof theicut the dies I118 be pulled forward off theworl; by releasing the fingers lfl l. I I

When a shortthread is to be cut'either inanually or by power, butespecially when operating by power, the operator 'can end the cut bypullfv ing the spider 5!! forward until ithe dies I68.

slide down the shoulders into the notches I38,- clearing the work. Theshoulders act in the same manner as the shoulders 36 in guidingthei'die.

teeth gradually out of the work while'the threading action is stillgoing on, and'so'finishing the threadswithout a bur. A

From theioregoing it will be'seen that I have invented a threadingtoolinwhich an advantageous gear ratio is obtained in ahand'tool re ducingthe pull which the operator has to ekert;

. Without increasingthe size: or'weight oft-he tool.

The direction in which the user turns the handies is'i -the same as-thedirection in which the cutting is accomplished, and in otherrespects the 1 operation of the improved. toolis familiar. 'The i use ofalead screw is avoided without lossofit's' advantages. Unwindin'g thetool'to take it or?v the pipe and to reset the leadscrew is-eliminated.Oncesetfor any-'depth 'of cuti'the-settingjean al ways be brought backwithout adjustment. by pulling the front and rear'partsaway fro'rnone.The elimination of 1 a' lead screw offers numerous advantages It savesthe-trouble and time of unwindingaftera out; itfpreventsjamming andbreakage; it permits threads of different lead to be cut by the samethreading tool with different dies.

As to, the saving of time, the provision of in combination with the camslot, because by the use of the two features no unwinding, eithernotches on the receding studs is an advantage ing stud notch does notsave time where a lead I screw is used because unwindingof the leadscrew governs the time required, and takes as long whether or not thechasers ave to bebackedf,

Although cutting a thread "with the present tool (geared 3:5) takes 66%more turns of:th'e

handle than a gearless die stock requires to cut a thread of the samelength, nevertheless; for'the total cycle of one cut 16 f ewer turnsare.

needed than with a lead screw tool, because there is no backingofi'orunwinding. Othermodes of applying the principle of my inventionmay be employed instead of the one explained, change being made as,regardsthe respect to the forward end of said barrel and to the diehead, and gear connections between said driving ring, said die head andsaid barrel.

2. In a threading tool, a barrel, a work-clamping assembly on the rearof said barrel axiallyv and circumferentially movable with relationthereto, a die head on the forward end of said barrel and rotatable Withrespect thereto, a driving ring rotatable with respect to the forwardend of said barrel and to the die head, and gear connections betweensaid driving ring, said die head and said barrel.

3. In a threading tool, a work gripping assembly comprising aring andwork-clamping studs f therein, a barrel movable within said ring, camson said barrel engaging said studs and adapted to guide movement of saidbarrel with respect to said studs, a die head rotatable with respect tosaid barrel, and gear connections between sai die head and said barrel.

4. In a threading tool, in combination, means for clamping a work piece,a die head rotatable with respect to said clamping means, die carryingmeans in said die head, studs extending longitudinally through said diehead at points radially disposed from the center of said head, faces onthe inner sides of said studs inclined outwardly from front to rear,bottom faces on said dies coacting with said inclined faces and adaptedto rest thereon, a ring threaded to said clamping means and engaging'therearward extensions of said studs but rotatable relatively to saidextensions. p

5. A thread cutting tool comprising in combination a Work piecereceiving member, a die carrying member rotatably mounted on said workpiece receiving member, a driving member coaxially and rotatably mountedon said die carrying member, and a planetary reduction gear traindrivably connecting said driving member to said mon axis, planetaryreduction gear connections between said drivingring and said headadapted to rotate said head slower than said ring but in the samedirection, a work piece receiving barrel differentially connected tosaid gear train, and cam means connecting said'barrel to the work piecefor urging said barrel in the same axial direction as that of: said diehead during thread cutting operation.

7. In a threading tool in combination, a'die head and a driving ringboth rotatable on a common axis, planetary reduction gear connectionsbetween said driving ring and said head adapted to rotate said headslower than said ring but in the same direction, a work piece receivingbarrel differentially connected to said gear train,

a work piece clamp with respect to which said barrel is slidable, and acam of compound curvature on said barrel engagejable with a fixedbearing element carried. by said work piece clamp.

8. In a threading tool, a work piece receiving member, a die carryingmember with radially movable dies rotatably, mounted on saidwork piecereceiving member, a driving member coaxially and rotatably mounted onsaid die carrying member and a reduction gear train drivably connectingsaid driving member to said die carrying member and to said work piecereceiving member, clamping means for attaching said work piece receivingmember to the work piece, axially extending studs mounted in said diecarrying member and having inclinedcfaces adapted to bear against andradially move said dies, and means for longitudinally adjustablyconnecting said studs to said clamping means.

- WILLIAM M. EMERY.

